The present invention disclosed herein relates to a superluminescent diode and a method of manufacturing the same, and more particularly, to a high-speed operable superluminescent diode, a method of manufacturing the same, and a wavelength-tunable external cavity laser including the same.
Wavelength division multiplexing (hereinafter, referred to as a “WDM”) is the next-generation optical transmission technology for increasing communication capacity and speed. To realize economical WDM optical access network systems, it is necessary to develop light sources which are stable and have a low-cost light source. For example, the WDM optical access network systems may be realized using planar lightwave circuit external cavity lasers (hereinafter, referred to as “PLC-ECLs”) using low-cost polymer and silica waveguides.
The Bragg grating of a PLC-ECL is disposed on silica and polymer waveguides on a silicon substrate, and a light source of that is hybrid integrated with a PLC device. The superluminescent diode (SLD) has been used as a suitable light source for the PLC-ECL, since its spectral width can cover the full band of WDM optical access network systems and it has a characteristic of stable reflectivity of less than 0.1% due to avoid reflection at the interface between the SLD and the PLC device. The performance of PLC-ECL is affected by the characteristics of SLD. The SLD usually has a wide spectral width, there is a limit in the reflectivity reduction achievable by using only an antireflection (AR)-coating. To reduce the reflectivity and to obtain a ripple less than 3 dB, the waveguide is tilted by 7˜15° with respect to the cleaved facet, and front facet is AR-coated.